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Canberra-based naturalist, conservationist, educator since 1980. I’m passionate about the natural world (especially the southern hemisphere), and trying to understand it and to share such understandings. To that aim I’ve written several books (most recently 'Birds in Their Habitats' and 'Australian Bird Names; origins and meanings'), run tours all over Australia, and for the last decade to South America, done a lot of ABC radio work, chaired a government environmental advisory committee and taught many adult education classes – and of course presented this blog, since 2012. I am the recipient of the Australian Natural History Medallion, the Australian Plants Award and most recently a Medal of the Order of Australia for ‘services to conservation and the environment’. I live happily in suburban Duffy with my partner Louise surrounded by a dense native garden and lots of birds.

Thursday 18 July 2024

Corymbia; ghosts, blood and spots!

This is my first post for a while as we've been exploring the wonders of south-western Queensland, as I mentioned in my last post. We brought back plenty of material for future posts, but for now I'm going to offer something different while I sort out my photos. I also thought this one might be a relatively easy one with which to ease myself back in (my mind is still back with big blue skies, huge horizons, narrow roads stretching out of sight ahead, and surprises round each corner). However, as usually happens in such a situation, it's been a lot more work than I'd realised, as I discovered how much I didn't know and, with new knowledge, came across a couple of misidentifications in my photos. All for the good, I know.

Today I'm talking about an important group of eucalypts, including a few pretty familiar ones, which are no longer called Eucalyptus. That might sound contradictory, but in fact 'eucalypt' is a general name to describe any of the trees that have at some time been called Eucalyptus; they remain as closely related to each other and as instantly recognisable as they ever were.

Flowers of Red Bloodwood Corymbia gummifera, here at Tianjara Falls in Morton
National Park inland from Nowra, south coast NSW. There are a couple of issues here
that are relevant to today's post, the first being the way the flowers are clustered. You may not be
able to see it well here, but the relatively flattened shape of each flower cluster is caused
by the different lengths of the flower stems within the cluster. The lower stems are longer
than the higher ones, so the overall shape is flat, or only slightly domed. This, in botanical
terms, is a corymb, which is different from the way in which other eucalypt flowers grow,
hence the genus name - more on that in a couple of paragraphs time!

The other thing to note in the above caption is the name of the tree. 'gummifera', naturally enough, means 'bearing gum' and while we may not think this remarkable, many early Europeans who encountered eucalypts certainly did. In 1688 the English pirate-naturalist William Dampier reported from the far north-west of Australia that "the Gum distils out of the knots or cracks that are in the bodies of  the trees". Governor Arthur Phillip, who commanded the first British colony on what is now Sydney Harbour, used the term 'gum-tree' in 1778; he collected this gum, and send samples back home, doubtless to have its commercial potential tested. The German botanist Joseph Gaertner first used the name gummifera in a description, but it was Daniel Solander, who sailed with Cook and Banks in 1770 and became the first university-trained botanist to land in Australia, who formally described it in 1788. 

However more than 200 years later the respected botanist Lawrie Johnson of the Royal Botanic Gardens in Sydney, along with colleague Ken Hill, grasped a very large and forbidding nettle indeed when he tackled the problem of what to do about Eucalyptus. The problem, in a gum-nut shell, is that the differences between Eucalyptus and Angophora are no greater than between the various sub-groups of Eucalyptus. Logic demanded either incorporating Angophora into Eucalyptus, or splitting Eucalyptus; Lawrie boldly chose the latter. Before his sad death from cancer in 1997 he had got as far as separating out the bloodwoods, spotted gums and ghost gums as Corymbia; they remain in most books now as the only other non-Eucalyptus eucalypt. There are four sub-groups within Corymbia; in simple terms they are the red bloodwoods (59 species), the yellow bloodwoods (11 species), the ghost gums (24 species) and the spotted gums (3 species). (There are also three outliers, but we won't worry about them today). 

That's about as technical as I'm going to get here - for the rest I'll introduce members of the four main groups and we can just admire them! Many of the bloodwoods, including those most familiar in the south-east, readily 'bleed' sap on the trunk, often encouraged by the gnawing of glider possums.

Desert Bloodwood Corymbia opaca near Windorah, south-west Queensland,
'bleeding' copiously, though not to any detriment! This species was separated
from the much more widespread C. terminalis (see below) in 1985, though
not everyone accepts the distinction.
Many of this group have plated bark, like this one, though not all.
Red Bloodwood again, near Narooma on the NSW south coast.

Pink Bloodwood C. intermedia (like most tree 'colour' names, the pink refers
to the timber, not that I've ever seen it). This one was in the Coffs Harbour Botanic
Gardens on the north coast of NSW, though it is an original tree.
These last two species are trees of the temperate south-east, though a couple of other well-known red bloodwoods are from the south-west (though are not called 'bloodwood').

Red-flowering Gum Corymbia ficifolia, in Wagga Wagga Botanic Gardens.
This small tree has a very small natural distribution in the south-west of Western Australia,
mostly along roadsides, but is very widely planted in gardens and road verges across
southern Australia. This photo shows the corymbs fairly clearly.

Marri C. calophylla, Darling Ranges near Perth. This is a very impressive
tree which dominates some dry forests in the south-west, often along with
Jarrah Eucalyptus marginata. Its big hard fruits (very like those of the Red-flowering Gum
above) are key food for the Red-capped Parrot and the Endangered Baudin's
(or, more helpfully, Long-billed) Black Cockatoo, both of
which extract the tiny seeds with a thin elongated upper mandible.
Others, like the Desert Bloodwood above, are restricted to the arid inland and the seasonally dry north.

Inland, or Desert Bloodwood C. terminalis, above and below. The one above
is in Currawinya NP, in south-west Queensland, and the one below in
Boodjamulla/Lawn Hill NP in monsoonal north-west Queensland,
with torrential summer rains and arid winters.

I'm especially fond of this species, and I see it on any inland trip to the northern half
of Australia, in four of the five mainland states and the Northern Territory.
 Another closely related desert bloodwood was only recognised in 1995.

Sand Dune Bloodwood C. chippendalei, Great Sandy Desert, central eastern WA.
This one only grows on dunes in the central and western deserts.
It was named for George Chippendale, an expert on plants of the Northern
Territory and later the author of the mighty eucalypts volume of the Flora of Australia.
He was also a lovely person who delighted in sharing his knowledge with others.
Corymbia deserticola (another 'Desert Bloodwood' though without a formal English name)
also growing in the Great Sandy Desert. It has a similar distribution to the Sand Dune
Bloodwood, but a wider range of habitats though is usually found on the plains.
Other red bloodwoods grow only in the seasonal tropics.
Small-fruited Bloodwood C. dichromophloia, Boodjamulla/Lawn Hill NP.
This common bloodwood is found from north-west Queensland to the Kimberley.
It is smooth-barked except for the base of the trunk, to which flakes of old bark adhere.

(Another) Red Bloodwood C. erythrophloia, Undara Lava Tubes, north Queensland.
This very striking tree grows in eastern tropical Queensland.
The yellow bloodwoods are much fewer in number. This one is common, and especially conspicuous.

Yellow Jacket C. leichhardtii, Salvator Rosa NP, south-central Queensland
(part of the Carnarvon Range), above and below. This is its southern-most extent,
but it extends north on the western slopes to Mareeba and is readily seen on a
drive through the Queensland tropical woodlands, where sandy soil overlays sandstone.
And one familiar to readers from the Sydney region, is Yellow Bloodwood C. eximia, also found only on sandstone, from Nowra to the Hunter Valley.
Yellow Bloodwood, here at Glenbrook in the Blue Mountains
(and I really must get a better photo of this species!).
There are just three species in the spotted gum group, including the well-known Queensland endemic Lemon-scented Gum C. citriodora - well known because it is widely planted in southern Australia. I used to walk to university in Adelaide through a large stand of them in Botanic Park. However further south by far the best known spotted gum is, wait for it... Spotted Gum C. maculata, which grows all along the NSW coast south from Taree. It is a lovely and readily recognisable tree for its blotchy bark, caused by grey flakes of old bark sticking to the trunk. Here are three Spotted Gum portraits from the south coast of NSW - I'm very partial to them!
Spotted Gum forest along a walk to the beach, Murramarang NP.
Tall old Spotted Gum near Nowra - I couldn't get far enough away to fit
it all into a conventional photo.
Spotted Gum forest with typical understorey of Burrawang cycads,
Macrozamia communis, near Nelligen.
Finally, the last group of Corymbia comprises the wonderful ghost gums, which I blogged about in more detail seven years ago here. By far the best known is the Ghost Gum of central Australia, from eastern WA to western Queensland.
A Ghost Gum C. aparrerinja, estimated to be at least 300 years old, at Trephina Gorge,
eastern Tjoritja (MacDonnell Ranges). For more photos of this very beautiful species,
and some interesting information I was given about the origin of the unusual
species name, see the link immediately above.
Ghost Gum by the road west of Windorah, south-west Queensland.
This must be close to its south-eastern limits.
(It occurs slightly further east to the north of here, at Barcaldine.)
Other ghost gums occur in the tropics.
Rough-leaved Ghost Gum C. aspera, Boodjamulla/Lawn Hill NP. The species is
found across the northern tropics from here in north-west Queensland to the Kimberley.

Ancient C. blakei in Bladensburg NP in central Queensland, growing on
a substrate too hard to penetrate with its roots! It is restricted to this part of Queensland.

Two others in the ghost gum group are very striking trees from eastern Queensland, though to my frustration my photos don't do them justice. Oh well, I'll just have to go back!

Dallachy's Ghost Gum C. dallachiana, Barcaldine. This is a young tree (and drought-affected)
and doesn't give much indication of how handsome it will grow up to be!
And we end with another favourite of mine, the stately Carbeen, or Moreton Bay Ash
C. tessellaris. Heading north we encounter this tall white tree with a rough grey or black
bark stocking in northern NSW, and it continues right up to Cape York.
Well, if this topic didn't interest you much, you won't be still reading! For those who are, thank you for persevering and I hope you learnt something of interest (I certainly have) and at the least enjoyed some of the trees themselves. Next time I'll be back with a more general posting, almost certainly based on one of the lovely parks we've recently spent time in, in south-western Queensland.

NEXT POSTING THURSDAY 8 AUGUST
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6 comments:

Anthony said...

That was an excellent read and great pics!
I'm glad you mentioned gliders.
I love the dark, rich honey that bees produce from the red bloodwood on the south coast, so good!

Ian Fraser said...

Thanks Ant, I really appreciate your taking the trouble to comment. Yes in retrospect the animals were rather shut out of this one, so the brief mention of gliders had to represent them all! Not sure I’ve tried Red Bloodwood honey, but it sounds as though I should!

Jane said...

Hello Ian, I'm new here! However this post caught my eye as I recently came across the attached paper which argues that Corymbia (and others) should never have been split off from Eucalyptus in the first place! I'm not a scientist so I haven't read the whole thing but perhaps it will be of interest. https://onlinelibrary.wiley.com/doi/10.1002/tax.13240

Ian Fraser said...

Hello Jane (from Torquay?), and thank you for this. I'd not come across the paper, though it's so very recent that it's probably not surprising. One thing to remember is that ultimately it's all a question of (well-informed) subjectivity. Mostly the nature of the relationships isn't in question, it's just a matter of whether we call the groupings genera or subgenera (etc etc). It's become a habit of botanists (but not zoologists) in recent times to create massive taxa by lumping together genera or even families. Perhaps it makes it simpler, but I do think we lose a great deal of nuance in actually understanding relationships, which is ultimately one of the key functions of taxonomy. However there's no 'right or wrong'. But, while I've not yet finished reading the article, I find it curious that they're perturbed by the 'problems' caused by splitting genera with the resultant required name changes, but not by the same problems caused by lumping two or more genera into one. I suspect a hidden agenda there! Again my thanks for bringing this to my attention. best, Ian

Jane said...

It'a all very interesting and I'm not taking a position one way or the other. However it's true when I first learned the name of the Corymbia ficifolia, as a layperson I did think "but that's a Eucalypt!" :)

Ian Fraser said...

And, in my opinion at least, you were and are right. 'Eucalypt' used in everyday language is like 'wattle' or 'duck'. All the plants that used to be called eucalypts should still be - we've only changed the formal relationships within the group and that's quite rightly of no interest to most people. We use 'duck' for a whole range of related genera. Anyway, these things are never as interesting as the organisms themselves and often say as much about us as about the organism. Thanks for your interest!